Glucose plays a vital role in providing biochemical energy. We are familiar with its chemical formula C6H12O6 and may even be familiar with diagrammatic representations of its ring-like molecular structure. We may also be aware of the ratio of its atoms C:H:O being 1:2:1. In particular, the ratio of hydrogen (H) to oxygen (O) is 2:1 and that, of course, is the same as in water. Not everybody notices this until told, and then there is something of a ‘eureka’ moment. Thus, another way of thinking about the glucose molecule that is also not immediately obvious is thinking of it as 6 carbon atoms and 6 water molecules. Indeed, the chemical formula for all of the simple sugars is (CH2O)n (where n is a number greater than or equal to 3). Put simply, each sugar is a carbon atom and a water molecule n times over, depending on the sugar in question.
This in turn takes us back to where sugar comes from: plants and photosynthesis. Here in very simple terms, a molecule containing one carbon atom (carbon dioxide) and a water molecule are turned into glucose—with some oxygen left over and released into the atmosphere for us to breathe.